Question

The bonds present between amino acids of a polypeptide chain are called

• A. glycosidic bonds
• B. peptide bonds
• C. phosphodiester bonds
• D. metallic bonds

Answer 1

The correct option is B peptide bonds

Amino acids undergo condensation reactions and join together to form proteins. Condensation reactions are those that combine two reactants with a loss of a small molecule, in this case, the water molecule. This is accomplished by the formation of peptide bonds. A peptide bond (-CONH-) is formed when the carboxyl (-COOH) group of one amino acid reacts with the amino (-NH${}_2$) group of the next amino acid. This linkage proceeds by the elimination of a water molecule.

In a polysaccharide, the individual monosaccharides are linked by a glycosidic bond (-C-O-C-).

In a nucleic acid, a phosphate moiety links the 3’ - carbon of one sugar of one nucleotide to the 5’ - carbon of the sugar of the succeeding sugar. This is called the phosphodiester bond $(-O-HP{O}_2-O-)$.

The forces that keep the atoms in a metal closely bound together on account of the force of attraction between metal ions and the mobile electrons are called metallic bonds.